This patent relates to a method for manufacturing a photo mask, and more particularly to a method for manufacturing a photo mask which can easily and effectively correct the line width of a mask pattern on the photo mask.
In general, various patterns of a semiconductor device are formed by photolithography technology including an exposure process and a development process using a photo mask.
However, during the process of manufacturing a photo mask, a critical dimension (CD) error or uniformity error may be exhibited in a mask pattern included in the photo mask due to various factors. Especially, a CD error in the mask pattern occurs when the mask pattern forms a line width larger or smaller than a desired line width. When the CD error in the mask pattern occurs, various patterns of a semiconductor device may have a line width different from the desired one, which may generate a error.
Therefore, such CD error in the mask pattern must be corrected, or if the correction is difficult the photo mask should be discarded.
Conventionally, when a CD error in the mask pattern was confirmed, via for example scanning electron microscope (SEM), the photo mask containing the CD error is to be discarded, and the conditions for manufacturing a photo mask, for example an electron beam exposure condition, were adjusted such as to re-manufacture a photo mask. Substantially, there is no way of using the photo mask with the CD error by correcting the line width in the mask pattern.
Therefore, the CD error effected as one factor for lowering production yield of photo masks. Moreover, even though the conditions for manufacturing the photo mask are adjusted, there is no way to confirm before hand whether or not the CD error will occur and such conditions are not easily adjusted, as a result the CD error also effected as a factor for lowering productivity and economical efficiency in the manufacturing method of a photo mask.